Crude Unit Preflash Drums and Columns

Preflash drums and preflash columns have significant effect on crude charge hydraulics. The reason for using preflash equipment are discussed, including general design considerations and problems that are created if they are designed incorrectly.

Read More
CDUGrant Niccum
Refiners Must Optimize FCC Feed Hydrotreating When Producing Low-sulfur Gasoline

Meeting lower gasoline product sulfur levels requires understanding sulfur distribution and species as function of the FCC gasoline boiling range. Gasoline pool sulfur limits can be achieved by minimizing contaminants in the cat feed hydrotreater (CFHT) feed and improving fractionation between gasoline and LCO. In many cases these options are much less expensive than designing the CFHT based on high-contaminant feed resulting from poor distillation unit performance.

Read More
FCCUGrant Niccum
Refiners Processing Heavy Crudes Can Experience Crude Distillation Problems

World heavy crude volumes are increasing, and as a result CDU/VDU operating problems and the frequency of unscheduled outages is also increasing. Conventional CDU/VDU designs will not operate reliably or profitably on the more challenging crudes. This article addresses problem areas and identifies specific sections requiring investment to maintain profitability throughout a 4-5 year run length for refiners processing heavy crudes.

Read More
CDU, VDUGrant Niccum
Revamping FCC Units: Debutanizer Reboiler Fouling

FCC debutanizer reboiler shell-side fouling causes unscheduled outages and can make bundle removal difficult or impossible. Expensive solutions such as the addition of a parallel reboiler system only treat the symptoms, not the causes, of the problem. FCC debutanizer fouling is caused by di-olefin polymerization and poor exchanger design. Improved exchanger design has eliminated unscheduled outages in several FCC’s.

Read More
FCCUGrant Niccum
Understanding Centrifugal Compressor Performance in a Connected Process System

Understanding how FCC and Delayed Coker wet gas compressor capacity is impacted by system pressure drop allows low cost changes to be made without expensive compressor modifications. In many instances high pressure drop caused by poor system design reduces unit capacity, lowers conversion, or raises column operating pressure. This article presents several solutions for increasing compressor capacity through inexpensive process system modifications.

Read More
FCCUGrant Niccum
Approaching the Revamp

The process design approach to new plant building can be costly if applied to a revamp, but an alternative is to integrate the heat and material balance and the equipment evaluation into the process flow sheet modeling.

Read More
Grant Niccum
Catalyst Changes, Downstream Improvements Increase FCC Propylene Yields

Increasing propylene yields from an FCC can be an attractive alternative to a steam cracker. Reactor and catalyst system changes can lead to much higher propylene yields than conventional FCC operations. Increasing propylene yields place additional demands on the gas plant, which need to be evaluated as part of the decision-making process. Otherwise valuable C4- products could be lost to fuel gas.

Read More
FCCUGrant Niccum
Field Data, New Design Correct Faulty FCC Tower Revamp

A large US Gulf Coast refinery had poor fractionation in their FCC main column after replacing trays with structured packing. Large amounts of gasoline were being downgraded to LCO because low cost liquid distributors were used. Packed main fractionators offer theoretical improvements, but are less forgiving than trayed columns so proper design and inspection are paramount. Once the design errors were corrected the fractionating problems were eliminated and unit goals were achieved.

Read More
FCCUGrant Niccum
Crude Overhead System Design Considerations

Proper crude unit overhead system is important when building a new unit or revamping an existing one to process different crudes. Overhead condenser designs should meet the specific processing objectives, such as distillate yield, run length and energy recovery.

Read More
CDUGrant Niccum